The conventional lead accumulators have many limitations in handling or transportation arising from the use of an electrolyte liquor, i.e., dilute sulfuric acid.
In order to solve this problem, various attempts have been made to fix the electrolyte liquor to make it non-fluid. For example, there have been proposed a glass fiber system composed of fine glass fibers each having an average diameter of about 1 .mu.m having been impregnated with an electrolyte liquor and a gel system obtained by mixing an electrolyte liquor with a gelling agent, such as a silicon dioxide powder.
However, the above-described fine glass mat is expensive. Further, since it undergoes shrinkage during use to lose intimate contact with the grids, it is necessary that the mat should be assembled while being in a compressed state. In particular, when the mat is applied to a large-sized battery, an ascent of the electrolyte liquor toward the upper ends of anode and cathode grids is suppressed, resulting in deterioration of characteristics in the upper portion.
On the other hand, in the above-described gel system, it is difficult to uniformly gelatinize the electrolyte liquor with silicon dioxide which is generally used as a gelling agent. In order to improve the gelling properties, it has been proposed to use silicon dioxide in combination with a sulfate, e.g., sodium sulfate, as a gelling assistant as described in Japanese Patent Application (OPI) No. 267274/86 (the term "OPI" as used herein means "unexamined published Japanese patent application"). There has also been proposed a method comprising mixing a silicon dioxide powder and a synthetic resin powder, sinter-molding the mixed powder into a sheet, and adding sulfuric acid thereto to form a gel as described in Japanese Patent Application (OPI) No. 10858/87.
These proposals, however, are still unsatisfactory in view of limitations of shape and volume, economy, and the like. Therefore, it has been keenly demanded to develop an effective method for fixation of an electrolyte liquor for lead accumulators.